Toll-like Receptor Research Articles

Endothelial cell-released mitochondrial DNA promotes B cell differentiation and virus replication during severe fever with thrombocytopenia syndrome virus infection.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease acquired through tick bites. We have previously demonstrated the correlation between SFTSV-induced mitochondrial dysfunction and inflammation induction, disease progression, and fatal outcome. In the current study, our clinical observation study establishes a strong correlation between elevated levels of circulating cell-free mtDNA and poor prognosis. In vivo studies further reveal endothelial cells as an important source responsible for releasing mtDNA into circulation, which promotes B cell activation, migration, and differentiation via Toll-like receptor 9 (TLR9). Notably, TLR9 activation enhances B-cell susceptibility to SFTSV infection. These findings suggest that mtDNA released by injured endothelial cells facilitates B cell differentiation and virus replication, emphasizing the significant role of mitochondrial damage within endothelial cells in contributing to the severity of SFTS outcomes.IMPORTANCESevere fever with thrombocytopenia syndrome (SFTS) is a new acute tick-borne infectious disease with a high fatality rate of 10%-50%. There is a strong correlation between SFTSV-induced mitochondrial dysfunction and inflammation induction, disease progression, and fatal outcome. Our research has revealed the crucial role of mtDNA in predicting the prognosis of SFTS and its impact on vascular endothelial injuries as well as B cell differentiation, two previously unexplored features of SFTSV infection. Moreover, mtDNA could activate the TLR9 signal to induce plasmablast differentiation in B cells and promote SFTSV infection. This study provides valuable mechanistic and clinical insights into the adverse outcomes associated with SFTSV infection.

Regulatory T cells suppress TLR9-induced formation of intrahepatic myeloid-cell aggregates for T cell population expansion in liver.

Toll-like receptor (TLR) 9 ligand has been reported to induce the formation of intrahepatic myeloid-cell aggregates for T cell population expansion (iMATEs), which enhances responses of cytotoxic T lymphocytes (CTLs). However, little is known about how the formation of iMATEs is regulated. Previously, various studies have demonstrated that regulatory T cells (Tregs) can suppress CTL responses through soluble cytokines or co-inhibitory molecules. It's unclear whether and how Tregs regulate the formation of iMATEs. In this study, we investigated whether Tregs are involved in regulating TLR9-induced iMATEs formation and the mechanisms behind it by using different gene knockout mice and blocking antibodies. We observed that intravenous injection of TLR9 ligand CpG induced significant iMATEs formation, accompanied by a marked increase in the number of Tregs infiltrating the liver as well as upregulation of IL-10 in both peripheral blood and liver. Importantly, depletion of Tregs either by anti-CD4, anti-CD25 blocking antibodies or diphtheria toxin (DT) in DEREG transgenic mice resulted in enhanced CpG-induced iMATEs formation. Conversely, knocking out IL-10 led to increased intrahepatic Treg infiltration and decreased CpG ODN-induced iMATEs formation. Consistently, depleting Kupffer cells (KCs), one of the main source of IL-10, also resulted in reduced formation of iMATEs. In conclusion, our results suggest that IL-10 suppresses Treg infiltration in the liver and thus promote CpG ODN-induced iMATEs formation. These results fill the gap in our understanding of the intrahepatic regulation mechanism of iMATEs formation.

Drosophila melanogaster Toll-9 elicits antiviral immunity against Drosophila C virus.

Insects rely on innate immunity and RNA interference (RNAi) to combat viral infections. Our study underscores the pivotal role of Drosophila Toll-9 in antiviral immunity, aligning with findings in Bombyx mori, where Toll-9 activation upregulates the RNAi component Dicer2. We demonstrate that Drosophila Toll-9 functions as a pattern recognition receptor (PRR) for double-stranded RNA (dsRNA) during Drosophila C virus (DCV) infection, akin to mammalian Toll-like receptors (TLRs). Toll-9 activation during DCV infection leads to the upregulation of Dicer2 and Argonaute2 and dephosphorylation of AKT. This study also reveals that Toll-9 localizes in endosomal compartments where it interacts with dsRNA. These insights enhance our understanding of Drosophila innate immune mechanisms, reflecting the evolutionary conservation of immune responses across diverse species and providing impetus for further research into the conserved roles of TLRs across the animal kingdom.

Diabetes mellitus aggravates myocardial inflammation and oxidative stress in aortic stenosis: a mechanistic link to HFpEF features

BackgroundPatients diagnosed with both aortic stenosis (AS) and diabetes mellitus (DM) encounter a distinctive set of challenges due to the interplay between these two conditions. This study aimed to investigate the effects of DM on the left ventricle in AS patients, specifically focusing on the inflammatory response, oxidative stress, and their implications for cardiomyocyte function, titin phosphorylation, and the nitric oxide (NO)-soluble guanylyl cyclase (sGC)-cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG) signaling pathway.Methods and resultsLeft ventricular myocardial biopsies (in total: n = 28) were obtained from patients with diabetic AS (n = 11) and compared with those from non-diabetic AS patients (n = 17). Enzyme-linked immunosorbent assay (ELISA) demonstrated significantly elevated levels of pro-inflammatory mediators, including high mobility group box protein 1 (HMGB1) and calprotectin, as well as receptors associated with the inflammatory response, such as Toll-like receptor 2 (TLR2), 4 (TLR4), and receptor for advanced glycation endproducts (RAGE). These were correlated with an enhanced NOD-like receptor protein 3 (NLRP3) inflammasome and the release of interleukins (IL) 1, 6, and 18 in diabetic AS patients compared to their non-diabetic counterparts. Additionally, in the diabetic AS cohort, there was an increase in oxidative stress markers (hydrogen peroxide (H2O2), 3-nitrotyrosine, lipid peroxidation (LPO), oxidative glutathione (GSSG)/reduced glutathione (GSH) ratio) within the myocardium and mitochondria, accompanied by impaired NO-sGC-cGMP-PKG signaling, decreased titin phosphorylation, and increased passive stiffness (Fpassive) of cardiomyocytes relative to non-diabetic AS patients. In vitro anti-inflammatory treatment with an IL-6 inhibitor and antioxidant treatment with GSH effectively normalized the elevated Fpassive observed in AS patients with DM to levels comparable to the non-diabetic group. Furthermore, treatment with PKG and the sodium-glucose cotransporter 2 (SGLT2) inhibitor empagliflozin also resulted in a reduction of Fpassive in cardiomyocytes from diabetic AS patients, although not to the levels observed in non-diabetic AS patients.ConclusionDM exacerbates inflammation and oxidative stress in AS patients, leading to impaired NO-sGC-cGMP-PKG signaling and increased cardiomyocyte Fpassive. These conditions are reminiscent of the pathophysiology of heart failure with preserved ejection fraction (HFpEF). These alterations can be ameliorated through anti-inflammatory and antioxidant therapies, indicating potential therapeutic strategies for diabetic patients suffering from AS.Graphical abstract

Genetic Predisposition of TLR 1 and TLR 6 Polymorphisms to Schizophrenia Onset and Prediction of Treatment Response.

Immunological dysregulation was described as one of the underlying mechanisms of schizophrenia (SCZ). Indeed, altered inflammation triggered by toll-like receptors (TLR) complexes TLR2-1 and TLR2-6 has gained attention in SCZ pathophysiology and treatment response. However, the genetic contribution of TLR1 and TLR6 remains unclear. Therefore, the present study aims to explore the possible association of TLR1 and TLR6 polymorphisms with the genetic predisposition to SCZ and treatment response. The current study included 240 controls and 226 patients genotyped for TLR1 and TLR6 polymorphisms by PCR-RFLP. Genotypic, allelic, and haplotype associations with SCZ and between patient groups based on their response to treatment were analyzed. In the dominant model, TLR1-S602I GG+TG and minor allele were significantly higher in responders compared to controls (p = 0.004; OR = 3.0, p = 0.002; OR = 3.0, respectively). Before treatment, male patients with TLR1-S602I GG+TG and TLR6-S249P TT+CT showed significantly higher SAPS scores (p = 0.01) compared to TT carriers. In response to treatment, TLR1-S602I TT carriers demonstrated a significant decrease in SANS scores (p < 10-4). Moreover, SANS scores were significantly lower in GG+TG carriers compared to TT carriers (p = 0.01), after treatment. Furthermore, TLR6-S249P CC carriers showed a significant decrease in SANS scores (p < 10-4) in opposite to TT+CT carriers (p = 0.6) in response to treatment. Moreover, TLR1-S602I GG+TG revealed a significantly elevated onset age compared to TT in schizophrenic males (p = 0.01). To conclude, our findings suggest that TLR1-S602I and TLR6-S249P could be potential genetic factors for schizophrenia susceptibility and the prediction of treatment response, particularly in males.

Anti-inflammatory and anti-atherosclerotic potential of opuntiol, opuntioside-I, and opuntiol’s silver nanoparticles: The role of cytokines and chemokines

BackgroundDisruption of immune system leads to excessive inflammation and the development of serious autoimmune diseases including atherosclerosis, characterized by the accumulation of oxidized low-density lipoproteins (ox-LDL) and various immune cells, particularly macrophages in the arterial wall. Monocyte chemoattractant protein-1 (MCP-1), stimulated and recognized by ox-LDL and toll-like receptors (TLRs), respectively, triggers intracellular signaling cascades, leading to the excessively released of various cytokines and chemokines. The expression control at any level is of great importance in decreasing the overall cascade of immune responses and inflammation, specifically, atherosclerosis. One of the most promising areas of research in the pathogenesis of inflammation and atherogenesis is herbal medications and its bioactive compounds with better delivery to target the exact cell and tissues with high efficacy and fewer side effects in pharmaceutical exploration. Therefore, the aim of present study was to explore the anti-inflammatory effects of naturally derived compounds, i.e., opuntiol (OP), opuntioside-I (OPG), and opuntiol’s silver nanoparticles (OP-Ag) for achieving optimal therapeutic approach to address the underlying inflammatory processes in atherosclerosis and improving treatment outcomes. Zymosan-induced peritonitis mouse model and ox-LDL was employed to determine the inhibitory potential of these compounds on the expression levels of key cytokines and chemokines allied with the onset of inflammatory events during atherosclerosis.ResultsqRT-PCR and ELISA were employed to check the expression levels of various cytokines (IL-1β, TNF-α, IL-6), chemokines (MCP-1, KC), and a transcription factor (NF-ĸB). Significant reduction was observed in chemotaxis along with decreased expression of key intermediates in response to the natural extracts, i.e., OP, OPG. Its silver-based nanoparticles and OP-Ag in lower concentration enhanced the drug delivery with improved inhibitory roles.ConclusionOverall, the present findings hold promise for advancing the potential therapeutic effects of OP, OPG, and its OP-Ag nano-conjugates at minimum concentrations, especially in the inflammation characteristic of atherosclerosis context, by incorporating zymogen-induced ox-LDL model where it interacts with TLRs in triggering inflammatory responses, and subsequently simulate atherosclerotic conditions via upregulation of MCP-1.

Identification of a multiple DAMP scavenger mimicking the DAMP-binding site of TLR4 to ameliorate lethal sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Current treatments are limited to source control and supportive care, underscoring the urgent need for novel therapeutic interventions. Endogenous molecules released from stressed or damaged cells, known as damage-associated molecular patterns (DAMPs), exacerbate inflammation, organ injury, and mortality in sepsis. In this study, we discovered a novel therapeutic compound, opsonic peptide 18 (OP18), designed to scavenge multiple DAMPs, including extracellular cold-inducible RNA-binding protein (eCIRP), high mobility group box 1 (HMGB1) and histone H3, by facilitating their clearance via macrophages. OP18 was developed by identifying a 15-amino acid (aa) binding site within the extracellular domain of Toll-like receptor 4 (TLR4) shared by eCIRP, HMGB1, and histone H3, then extending it with an αvβ3-integrin binding RGD (Arg-Gly-Asp) motif, resulting in an 18-aa peptide. Our data show that OP18 binds strongly to the above DAMPs and interacts with αvβ3-integrin on macrophages, promoting phagocytosis of DAMPs and facilitating their lysosomal degradation. In vitro, OP18 reduced the production of the inflammatory cytokine TNF-α in DAMP-activated macrophages and restored mitochondrial function, as evidenced by improved oxygen consumption rate (OCR) and ATP production. In a lethal sepsis model induced by cecal ligation and puncture (CLP), DAMP levels were significantly elevated, while OP18 treatment markedly reduced the serum DAMP levels. Additionally, OP18-treated septic mice demonstrated reduced blood organ injury markers, decreased proinflammatory cytokine levels, attenuated ALI, and improved survival. These findings establish OP18 as a promising therapeutic molecule that reduces DAMP-induced inflammation, offering a potential strategy to improve outcomes in lethal sepsis.

Alterations and mechanistic insights of gut microbiota and its metabolites in type 2 diabetes mellitus and Alzheimer's disease

AbstractEpidemiological studies suggest a link between type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD), possibly due to gut microbiota dysbiosis, although the exact mechanisms are unclear. This narrative review uniquely addresses how gut microbiota‐derived metabolites mediate overlapping pathologies of insulin resistance, neuroinflammation, and amyloidogenesis in T2DM and AD, proposing a framework for dual therapeutic targeting. This narrative review provides an in‐depth examination of the roles and mechanisms of gut microbiota and their metabolites in the context of T2DM and AD. This study indicates that gut microbiota dysbiosis significantly impacts the pathogenesis and progression of both diseases by modulating metabolic pathways, immune functions, and inflammatory responses. Key bacteria, such as Akkermansia muciniphila (which releases outer membrane vesicles), Lactobacillus, and Bifidobacterium, as well as their metabolites like short‐chain fatty acids (SCFAs), bile acids (BAs), lipopolysaccharide (LPS), vitamins, and Trimethylamine N‐oxide (TMAO) regulate T2DM and AD through complex mechanisms. Multiple signaling pathways, including G‐protein coupled receptor 41/43 (GPR41/43), phosphoinositide 3‐kinase (PI3K)/protein kinase B (Akt), Toll‐like receptor 4 (TLR4)/nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB), and endoplasmic reticulum (ER) stress‐mediated pathways, are also involved. These findings offer insights into the pathogenesis and potential targeted therapies for T2DM and AD.

Electroacupuncture attenuates bone erosion and promotes macrophage polarization in a mouse model of collagen-induced arthritis.

The aim of this study was to investigate the effect of electroacupuncture (EA) on macrophage polarization and bone erosion in a mouse model of collagen-induced arthritis (CIA). C57BL/B6 mice were used to establish a CIA model and were treated with electroacupuncture (EA) at ST36 and SP6. At the end of the experiment, knee joints were harvested for hematoxylin-eosin (H&E) staining to detect knee synovitis. Immunohistochemistry (IHC) was performed to assess the expression of macrophage markers. The degree of bone destruction was evaluated using micro-computed tomography (CT), tartrate-resistant acid phosphatase (TRAP) staining and safranin-O fast green staining. Peripheral blood transcriptome sequencing was performed using Illumina high-throughput sequencing. Synovial membrane proteins were quantitatively analyzed by mass spectrometry. Differentially expressed genes and proteins were identified and the R software package was used to analyze the data. Compared with the model group, the arthritis index (P < 0.05) and inflammatory infiltration decreased (P < 0.05), cartilage destruction was inhibited (P < 0.01), the number of osteoclasts decreased (P < 0.05), knee bone erosion was alleviated and the M1/M2 macrophage ratio decreased (P < 0.01) in the EA group. The results of bioinformatics analysis showed that the differential genes between the EA and model groups were mainly enriched in rheumatoid arthritis (RA) and the peroxisome proliferator-activated receptor (PPAR) signaling pathway. Differentially expressed proteins were mostly enriched in the toll-like receptor (TLR) signaling and autophagy pathways. EA prevents bone erosion, reduces the M1/M2 macrophage ratio in synovial tissue, inhibits the TLR and autophagy pathways and reduces synovial invasion in a mouse model of CIA.

Gut Microbiota Modulates Obesity-Associated Skeletal Deterioration Through Macrophage Aging and Grancalcin Secretion.

Obesity is associated with skeletal deterioration and increased fracture risk, but the underlying mechanism is unclear. Herein, it is shown that obese gut microbiota promotes skeletal deterioration by inducing bone marrow macrophages (BMMs) senescence and grancalcin (GCA) secretion. Obese mice and those receiving obese fecal microbiota transplants exhibit increased senescent macrophages and elevated GCA expression in the bone marrow. In a study of 40 participants, it is found that obese patients are associated with higher serum GCA levels. It is further revealed that obese gut-microbiota derived lipopolysaccharides (LPS) stimulate GCA expression in senescent BMMs via activating Toll-like receptor 4 pathway. Mice with depletion of the Gca gene are resistant to the negative effects of obesity and LPS on bone. Moreover, neutralizing antibody against GCA mitigates skeletal deterioration in obese mice and LPS-induced chronic inflammation mouse model. The data suggest that the interaction between gut microbiota and the immune system contributes to obesity-associated skeletal deterioration, and targeting senescent macrophages and GCA shows potential of protecting skeletal health in obese population.

TLR2 promotes the progression of diabetes mellitus with atherosclerosis via activating NLRP3 inflammasome and MyD88/NF-κB signaling pathway

Atherosclerosis, a critical vascular complication frequently associated with diabetes mellitus, develops due to the synergistic effects of multiple pathological mechanisms. Toll-like receptor-2 (TLR2) has been identified as a key contributor to the progression of a wide range of disorders. The primary goal of this research was to investigate the functional role of TLR2 in the context of diabetes mellitus-associated atherosclerosis (DMA) and to delineate the molecular pathways underlying its effects. The study enrolled 30 DMA patients and 30 healthy individuals. An in vitro model of DMA was developed to mimic the disease state. TLR2 expression levels were measured using RT-qPCR, while pyroptosis rates were assessed via flow cytometry. Western blot analysis was utilized to determine protein expression levels. Co-immunoprecipitation was performed to assess the interactions between TLR2 and myeloid differentiation primary response 88 (MyD88). A DMA mouse model was established. Oil red O staining were used to assess the effect of TLR2 on lipid deposition. Elevated levels of TLR2 were observed in both clinical samples from DMA patients and the experimental DMA cell model. The DMA model exhibited reduced cell viability, increased pyroptosis rates, elevated levels of pyroptosis-related proteins, and higher concentrations of interleukin (IL)-1β and IL-18. These effects were reversed upon TLR2 inhibition. Furthermore, inhibition of TLR2 expression effectively blocked the activation of the MyD88/NF-κB signaling pathway. Conversely, TLR2 overexpression reduced cell viability, enhanced pyroptosis, and activated the MyD88/NF-κB pathway, effects that were counteracted by NF-κB inhibition. In in vivo study, silencing of TLR2 improved inflammation and atherosclerosis in diabetic mice. The results demonstrated that TLR2 drives the progression of DMA through the activation of the NLRP3 inflammasome and the MyD88/NF-κB signaling cascade. These findings suggested that TLR2 could be a promising target for therapeutic interventions aimed at treating DMA.

From receptor to response: dissecting the TLR4 pathway in diabetic neuropathy.

Diabetic neuropathy (DNP) is a common complication of diabetes that has a significant impact on the patient's quality of life. The primary objectives of clinical treatment for DNP these days are symptomatic pain management and glycemic control. Since there is currently no cure for nerve damage, the only objective is to alleviate discomfort and slow its progression. Pre-clinical research over the last decade has increasingly linked toll-like receptor 4 (TLR4)-mediated neuroinflammation as a major contributor to DNP development. The role of TLR4-mediated neuroinflammation in the pathophysiology of DNP is covered in this review, along with different therapeutic approaches that target TLR4-mediated neuroinflammation in DNP in pre-clinical research. Despite promising pre-clinical results, translating these findings into clinical practice remains a challenge, which we also discuss how to address and overcome in this review.

Necrotizing enterocolitis: specific human milk oligosaccharides prevent enteric glia loss and hypomotility.

Necrotizing enterocolitis (NEC) is mediated by toll-like receptor 4 (TLR4)-induced inflammation and is preceded by reduced intestinal motility. Human milk oligosaccharides (HMOs) are non-digestible components of breast milk that prevent NEC in preclinical models. We now hypothesize that HMOs can reduce the risk of NEC through restoration of intestinal motility and reduced TLR4-mediated inflammation. NEC was induced in C57-BL/6 mice through the combination of formula gavage, hypoxia, and oral administration of NEC stool. Mice were administered either 2'-FL (5 g/L), 6'-SL (5 g/L), or a blend of 5 specific HMOs (5 g/L) containing 2'-FL (2.606 g/L), 3'-FL (0.652 g/L), LNT (1.304 g/L), 3'-SL (0.174 g/L), and 6'-SL (0.260 g/L). Gastrointestinal motility was assessed by 70 Kd FITC-dextran transit time. Enteric glia were quantified by immunohistochemistry and qRT-PCR expression. Administration of either 2'-FL, 6'-SL, or HMO blend significantly attenuated NEC severity and reversed intestinal hypomotility. HMOs prevented enteric glia loss and regulated key genes critical for enteric glia maintenance, attenuated pro-apoptotic genes, and increased anti-apoptotic genes in vitro, resulting in a reduction in apoptosis. Strikingly, HMOs reduced LPS-TLR4-induced NFκB signaling and ROS generation in enteric glia. HMOs protect against NEC at least in part through protective effects on inflammation and the enteric nervous system. This study sheds light on the role of certain human milk oligosaccharides in a clinically relevant mouse model of NEC and adds additional insights into their underlying mechanism of action by revealing a protective effect on the enteric nervous system. These results reveal that HMOs prevent the loss of enteric glia in NEC and influence the expression of genes that regulate enteric glia maintenance. HMOs also limit TLR4-NFkB signaling, providing an additional mechanism of enteric glia maintenance.

Nephropathy II Decoction Attenuates Renal Fibrosis via Regulating TLR4 and Gut Microbiota Along the Gut-Kidney Axis.

Nephropathy II Decoction (NED) is a widely used Chinese medicinal formulation for managing chronic kidney disease (CKD). Despite its extensive application, the precise mechanisms underlying its therapeutic effects remain poorly understood. This study aims to elucidate the role of NED in attenuating renal fibrosis and to explore its impact on the gut-kidney axis. The principal constituents of NED were analyzed using ultra-performance LC-tandem mass spectrometry (UPLC-MS/MS). A bilateral renal ischemia-reperfusion injury (bIRI) model was employed to induce fibrosis. RT-qPCR was utilized to assess the expression of mRNA related to the toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) and nuclear factor-κB (NF-κB) signaling pathway. Western blotting analysis was performed to identify changes in renal fibrosis markers, TLR4/MyD88/NF-κB pathway proteins, and the colon proteins ZO-1 and Occludin-1. Serum levels of uremic toxins were quantified using enzyme-linked immunosorbent assay (ELISA), and 16S ribosomal RNA (rRNA) gene sequencing was conducted to explore changes in the gut microbiome of the mice. Our study demonstrated that mice in the NED group exhibited reduced serum creatinine, blood urea nitrogen, and urinary protein levels, alongside improvements in kidney damage and a decrease in renal fibrosis markers. In the bIRI group, TLR4/MyD88/NF-κB protein and mRNA levels, as well as intestinal tight junction proteins and enterogenic uremic toxins, were significantly reduced. NED treatment reversed these changes and modified the gut microbiota. Furthermore, fecal microbial transplantation (FMT) alleviated kidney damage and fibrosis in bIRI mice. In summary, NED ameliorates kidney injury and fibrosis by modulating the gut microbiota and may further attenuate fibrosis through the inhibition of TLR4 expression, thereby influencing the gut-kidney axis.

Designing a multi-epitope universal vaccine for concurrent infections of SARS-CoV-2 and influenza viruses using an immunoinformatics approach

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) and influenza viruses share several conserved epitopes that can be utilized for the development of universal vaccines. Our previous research demonstrated that recombinant M2e-HA2 (Matrix-2 ectodomain-Hemagglutinin subunit 2) proteins derived from influenza elicited an immune response against the virus, suggesting their potential use in universal influenza vaccine formulations. Given the lack of a specific vaccine to address SARS‑CoV‑2 and influenza co-infections, this study aimed to design a universal vaccine using immunoinformatics methodologies.MethodsIn this study, B-cell and T-cell epitopes were identified from the nucleocapsid (N) protein of SARS‑CoV‑2. Additionally, the N-terminal segments of M2e (SLLTEVET) and HA2 (GLFGAIAGF) from influenza were incorporated to construct a multi-epitope vaccine. Suitable linkers were designed, and human beta-defensin-2 was selected as an adjuvant. Further evaluations were conducted, focusing on key parameters such as stability, allergenicity, and antigenicity.ResultsThe major histocompatibility complex (MHC) class I and II binding epitopes exhibited broad population coverage for the vaccine on a global scale. The vaccine structure was found to interact with toll-like receptor 3 (TLR-3), and the docked conformation of the vaccine/TLR-3 complex demonstrated high stability during molecular dynamics (MD) simulations. The constructed vaccine exhibited thermal stability across cold, ambient, and human body temperatures. Additionally, in silico cloning of the vaccine candidate into the pET-28a(+) vector was performed to facilitate production within the Escherichia coli expression system.ConclusionOverall, the findings suggest that the designed vaccine has the potential to serve as an effective universal vaccine and a promising strategy for controlling both Coronavirus disease 2019 (COVID-19) and influenza on a global scale.

Amyloid β-Induced Inflammarafts in Alzheimer’s Disease

The formation of amyloid beta (Aβ) plaques is a central process in the development of Alzheimer’s disease (AD). Although its causative role or the effectiveness of therapeutic targeting is still debated, the key involvement of Aβ in the pathogenesis of neuroinflammation and neurodegeneration in AD is broadly accepted. In this review, we emphasize the role of lipid rafts, both in APP cleavage producing Aβ in neurons and in mediating Aβ inflammatory signaling in microglia. We introduce the term inflammarafts to characterize the Aβ-driven formation of enlarged, cholesterol-rich lipid rafts in activated microglia, which support protein–protein and lipid–protein interactions of inflammatory receptors. Examples reviewed include toll-like receptors (TLR2, TLR4), scavenger receptors (CD36, RAGE), and TREM2. The downstream pathways lead to the production of cytokines and reactive oxygen species, intensifying neuroinflammation and resulting in neuronal injury and cognitive decline. We further summarize emerging therapeutic strategies and emphasize the utility of apolipoprotein A-I binding protein (AIBP) in selective targeting of inflammarafts and attenuation of microglia-driven inflammation. Unlike the targeting of a single inflammatory receptor or a secretase, selective disruption of inflammarafts and preservation of physiological lipid rafts offer a novel approach to targeting multiple components and processes that contribute to neuroinflammation in AD.

Susceptibility from the immunological perspective of COVID-19-associated pulmonary aspergillosis: A literature review.

The incidence rate of COVID-19-associated pulmonary aspergillosis (CAPA) is rising. However, the pathogenesis of CAPA remains unclear. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection disrupts pathways related to type I interferon and Toll-like receptors, key components in innate immunity, thereby elevating the incidence of CAPA. Additionally, SARS-CoV-2 infection results in T and B cell functional deficiencies or exhaustion within adaptive immunity, weakening the defense against invasive Aspergillus. Furthermore, SARS-CoV-2 infection enhances the replication of cytomegalovirus and alters the gut microbiota, factors that may aid in diagnosing CAPA. Immunosuppressive therapy in COVID-19 patients is also believed to heighten the risk of invasive aspergillosis. Therefore, this review, examines the immune response to SARS-CoV-2 infection combined with invasive aspergillosis, and explores the pathogenesis and susceptibility factors of CAPA. We propose that variations in an individual's immune response significantly determine susceptibility to CAPA. The aim of this paper is to deepen clinical understanding of CAPA's pathogenesis, thereby aiding in mitigating susceptibility risk and advancing novel treatment approaches.

The Role of the Gut Microbiota in Female Reproductive and Gynecological Health: Insights into Endometrial Signaling Pathways

Fertility is a dynamic, multifactorial process governed by hormonal, immune, metabolic, and environmental factors. Recent evidence highlights the gut microbiota as a key systemic regulator of reproductive health, with notable impacts on endometrial function, implantation, pregnancy maintenance, and the timing of birth. This review examines the gut–endometrial axis, focusing on how gut microbial communities influence reproductive biology through molecular signaling pathways. We discuss the modulatory roles of microbial-derived metabolites—including short-chain fatty acids, bile acids, and tryptophan catabolites—in shaping immune tolerance, estrogen metabolism, and epithelial integrity at the uterine interface. Emphasis is placed on shared mechanisms such as β-glucuronidase-mediated estrogen recycling, Toll-like receptor (TLR)-driven inflammation, Th17/Treg cell imbalance, and microbial translocation, which collectively implicate dysbiosis in the etiology of gynecological disorders including endometriosis, polycystic ovary syndrome (PCOS), recurrent implantation failure (RIF), preeclampsia (PE), and preterm birth (PTB). Although most current evidence remains correlational, emerging insights from metagenomic and metabolomic profiling, along with microbiota-depletion models and Mendelian randomization studies, underscore the biological significance of gut-reproductive crosstalk. By integrating concepts from microbiology, immunology, and reproductive molecular biology, this review offers a systems-level perspective on host–microbiota interactions in female fertility.

Recombinant serralysin metalloproteases D enhances the intracellular replication of infectious bovine rhinotracheitis virus

Infectious bovine rhinotracheitis virus (IBRV) and Serratia marcescens co-infection are commonly observed in the respiratory tract of cattle subjected to respiratory diseases. However, the potential effects of proteases from Serratia marcescens on the IBRV infection remain poorly understood. In this study, we investigated the role of recombinant serralysin-like protease D (rSPD) in modulating IBRV infection in Madin-Darby bovine kidney (MDBK) cells. Our findings demonstrate that rSPD enhances IBRV replication and exacerbates the cytopathic effects of the virus on MDBK cells. Quantification of IBRV gB gene copy numbers using fluorescence quantification PCR (FQ-PCR) revealed that rSPD promotes viral replication during the intracellular stage, without affecting viral adsorption, entry, or directly interacting with viral particles. The transcriptomic analysis further demonstrated that rSPD suppresses innate immune responses while amplifying inflammatory pathways in IBRV-infected MDBK cells. Gene Ontology (GO) and KEGG enrichment analysis identified significant enrichment of differentially expressed genes (DEGs) in key signaling pathways, including JAK–STAT, NOD-like receptor, Toll-like receptor, TNF, NF-κB, and MAPK pathways. Notably, rSPD downregulated genes associated with innate immunity, such as ISG15, OAS2, IFIT1, IFIT2, IFIT3, MX1, RSAD2, MX2, SAA3, DDX58, IFI44, and IRF1, suggesting that rSPD suppresses host antiviral defenses. Conversely, rSPD upregulated genes involved in inflammatory response, including IL-6, IL-8, CCL2, CX3CL1, CCL3, and CXCL3, indicating that rSPD may exacerbate cellular damage and promote viral replication by inducing excessive inflammatory responses. These findings provide novel insights into the interplay between bacterial proteases and viral infections, highlighting the potential role of bacterial proteases in exacerbating viral pathogenesis and offering a foundation for further research into therapeutic strategies targeting bacterial-viral interactions.

Interferon and immunity: the role of microRNA in viral evasion strategies

Interferons (IFNs) are indispensable innate antiviral cytokines that orchestrate the vertebrate immune response against viral incursions. Nearly every cell possesses the remarkable ability to release IFNs upon detecting viral threats, triggering a robust signaling cascade that alerts neighboring cells and halts viral propagation via paracrine communication. The intricate influence of IFNs is mediated by an extensive network of proteins activated through the Jak-STAT pathways, facilitating the swift transcription of over 300 interferon-stimulated genes (ISGs) that fortify cellular defenses against replication. However, the cunning nature of viruses has led to the evolution of sophisticated evasion strategies, notably through the manipulation of host microRNAs (miRNAs) that disrupt vital components of the IFN signaling machinery. This review delves into the intricate interplay between viral infections and both host- and viral-derived miRNAs, exploring their potent roles in modulating RIG-I-like receptors, Toll-like receptors, IFN receptors, and the JAK/STAT pathway, ultimately shaping the landscape of antiviral immunity.